Project Summary Viruses are among the most worrisome carcinogens because of their abilities to be transmitted and mutate. The complex mechanisms associated with viral oncogenesis require a deep understanding of the fields of virology, molecular and cellular biology, genetics, immunology, and oncology. The oncoviruses presently include hepatitis B virus, hepatitis C virus, certain types of human papillomaviruses, certain herpesviruses, and most retroviruses. The research programs of trainers in this Training Program focus on four of the five groups of oncoviruses. This application is a competitive renewal for years 21-25 of a long-standing Training Program to support graduate students and postdoctoral scholars as they acquire the knowledge and skills to investigate viruses and cancer. The trainers associated with the proposed program have their primary academic appointments in the Departments of Microbiology and Immunology, Biochemistry and Molecular Biology, Pathology, Obstetrics and Gynecology, Pediatrics, and the Divisions of Hematology/Oncology in the Penn State Cancer Institute and Infectious Diseases in the Department of Medicine. Each of the trainers directs a well-funded and productive research program in areas of virology, immunology, and/or cancer biology. Trainers and trainees are associated with the Departments of Microbiology and Immunology, Biochemistry and Molecular Biology, Pathology, Hematology/Oncology, Pediatrics, Infectious Diseases, and the Penn State Cancer Institute, providing the predoctoral and postdoctoral trainees opportunities associated with multiple interdisciplinary programs that cross boundaries. A strength of the program is the numerous opportunities for interactions among the trainers, which contributes to the development of a highly supportive and interactive environment in which the trainees can reach their full potential as young scientists. The breadth of the scientific interests of members of the training faculty provides a blend of research areas within virology and immunology that facilitates an outstanding training environment. The Training Program is further enhanced by numerous seminars, journal clubs, symposia, and a new clinical oncology preceptorship program that enhance the training environment. In addition, the close association among many of the trainers with the Penn State Cancer Institute has enhanced the translational opportunities for young scientists with an interest in cancer. The research accomplishments of the faculty, their strong commitment for training, the availability of excellent core support facilities, and opportunities for extensive interactions all provide a dynamic training environment for the graduate students and postdoctoral scholars in the Viruses and Cancer Training Program.